White Phosphorus

Legal status

White Phosphorus is covered by Protocol III of the 1980 Convention on Conventional Weapons, which prohibits use of the substance as an incendiary weapon against civilian populations and in air attacks against military forces in civilian areas.
Though the UK and 80 other countries are signatories to protocol III, the United States is not, and has admitted to using it in Fallujah[1] and Mosul.[2]